Oil traders sold crude to book profits on Friday after strong data from major economies increased optimism about the state of the world economy and underpinned gains made during the week.

Brent crude oil futures ended the day unchanged, while US crude dropped, but posted its seventh straight weekly price increase, the longest such streak since early 2009.

Data published by the Munich-based Ifo think tank on Friday showed Germany's business morale rose to its highest level in more than half a year, indicating Europe's largest economy is gaining momentum.

News that European banks will repay 137 billion euros of emergency loans added support as investors took the move as a sign that the European banking system was recovering strength.

"We were up earlier on improving investor confidence in Germany and the ECB's announcement that they were going to help some of the financial institutions repay some of the loans earlier, which helped support the euro and pushed buying into the oil markets," said Gene McGillian, analyst at Tradition Energy in Stamford, Connecticut.

Brent settled unchanged from Thursday at $US113.28 a barrel, off the session high of $US113.84. US crude fell 7 cents to settle at $US95.88, off a high of $US96.56. Crude was up 0.3 per cent on the week.

Gasoline was the biggest daily gainer in the oil complex, rising 0.54 per cent, while heating oil declined despite cold weather gripping the Northeastern United States, a major consuming region for heating oil.

"One way of looking at this is as some rotation between markets. Seasonally, people might be giving up a little bit on the heating oil story and shifting toward gasoline, anticipating rising seasonal demand as we move into the spring," said Tim Evans, energy analyst at Citi Futures Perspective in New York.

Inventory data released on Thursday revealed lower-than-expected gasoline stocks in the United States, which Evans said could be supporting prices.

Traders were also monitoring the Seaway crude oil pipeline after it was forced this week to curtail deliveries to its Gulf Coast terminal, potentially reducing flows out of the delivery point for West Texas Intermediate crude oil futures at Cushing, Oklahoma.

Seaway operator Enterprise Products Partners said on Friday deliveries to its Katy, Texas, terminal in the Houston area were normal.